equinax
An event of some sort that happens twice a year.
bi-monthly
biennial and biannual, althou biannual could also mean twice a year
If something is biannual, it happens twice a year.
semimonthly
Bi-weekly means twice a week. A bi-weely event happens twice a week.
Biannual
biannual...
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An event occurs 2 times in a year
the letter E